Enclosed switch



0dr. l5, 1940. J. P. HEIM ENCLOSED SWITCH Filed Sept. '7, 1938 2 Sheets-Sheet l IN V EN TOR.

OC. 15, 1940. Jl pI HElM 2,218,028

ENCLOSED SWITCH Filed Sept. 7, 1938 P. Sheets-Sheet 2 INVENTOR. Just-Pf( P. HEIM,

/ TTORNEY.

Patented Oct. l5, 1940 ENCLOSED SWITCH Joseph P. Heim, New Britain, Conn., assigner to The Trumbull Electric Manufacturing Company, a corporation of Connecticut f Application September 7, 1938, Serial No. 228,782

6 Claims.

This invention relates particularly to what are sometimes termed front operated interlocking switches.

Patent 2,000,231 to C. D. Hepler shows one 5 type of switch to which this invention is applicable.

In such switches the stationary and movable contacts are enclosed in a box and an operating handle is mounted on the cover or iace plate and i vsuitably connected to the movable contacts, so that the circuit may be opened and closed by moving the handle in one direction or the other. Such switches are provided with fuses or circuit protecting devices inside the box and the face l plate is provided with an opening normally closed by a movable door. When the door is opened the fuses or circuit protecting devices are accessible through the opening. Such switches are commonly provided with means for preventing the opening of the fuse door when the circuit is closed.

One object of this invention is to prevent the accidental closing of the circuit when the fuse door is opened.

Another object is to provide a construction of the foregoing description in which the switch may be closed when the fuse door is in the open position by an operator familiar with the mechanism for the purpose of inspecting the mechanism 3" under load, etc.

I have sought to embody the improvements in an enclosed switch construction in which 'the fuse door may be opened and closed freely when the circuit is opened and the switch may be operated freely when the door is closed and in which, under normal conditions, the switch can not be closed when the fuse door is open but can be closed by an authorized operator while the fuse door is opened when there is occasion for such abnormal operation.

The foregoing results are obtained in a switch of this character by mounting the switch operating lever or handle on the face plate adjacent a door which normally closes an opening. The

43 movable switch contacts inside the box are actuated by this external handle. On the back of the face plate is mounted an interlocking member normally engaged by a projection on the door when the door is closed. This interlocking member co-acts with a part of the switch actuating mechanism inside the box to prevent the operation of the handle and the closing of the circuit when the door is opened. The operating lever 1s P provided with a projection whichoo-acts with the door to prevent the door from being opened wher` (Cl. 20G-50) the circuit is closed. When the door is opened, a portion of the interlocking member is exposed or accessible through the opening so that the interlock may be released manually if it is desired to close the circuit while the door is open. 5

Switches of this character usually embody snap action or quick break mechanism and this may be provided in such a switch either on the inside of the box or external thereto.

Fig. 1 is a front view of the switch embodying 10 one form of my invention, the parts being in the closed circuit position and parts being broken away so as to show the interlocking device.

Fig. 2 is a side view partly in section of the same. 1 Fig. 3 is a perspective view of the face plateI illustrating the interlocking mechanism.

Fig. 4 is a sectional view somewhat similar'to Fig. 2 but showing only the top plate and attached parts with the actuating handle in the 20 open circuit position and the door to the fuse compartment open.

The box body 5 may be of any suitable type and provided with a face plate 6 secured thereto in any suitable manner as for instance a number of screws 1.

In the box are mounted the stationary contacts 8a and circuit protecting devices 9, together with terminals of any suitable character.

The face plate has an opening III through 30 which the circuit protecting fuses 9 may be reached. This opening is normally closed by a door II hinged at I2 and provided with any suitable form of latch I3 for normally holding the door closed. `35

The operating lever or handle I4 is hinged at I5 to a projection I6 carried by the face plate.

The movable switch members I1 are carried by a bar I8 which passesy through an opening I9 in the face plate. This bar I8 is hinged at 20 to a u hinged member 2| which has a lost motion action for the operating handle through the medium of a spring 22 so that when the circuit is closed and the operating lever is pulled out, the spring 22 4., will be compressed and exert pressure on the pivoted member 2 I.

When the pressure overcomes the friction of the movable switch member II against the stationary contacts 8a, the spring will pull the lever 2| and 50 the bar I8 and attached movable switch member outwardly and open the circuit with a quick break action. The lost motion connection and spring action may, if desired, be interposed between the pull rod or bar Il and the movable switch member as is sometimes done in switches of this character.

In the form shown the operating lever I4 is provided with a projection 2| which, when the door is closed, stands in the path of the projection 25 carried by the door H to prevent the opening of the door.

On the back of the face plate is mounted a slide 26 guided by pins 21 and under tension o1' the spring 28 tending to move the slide toward the door opening l0 as shown in Figs. l and 2. This slide or locking bar 26 is held in ,the position of Figs. l and 2 by a wedgelike projection 30 carried by the cover, which projection presses against the inclined tip 3| of the locking bar. When the door Il is opened and this projection 30 withdrawn from the path of movement oi' the locking bar 2i, the spring 28 moves the locking bar from the position of Fig. 2 to the position of Fig. 3. The bar 26 has an opening 32 through which the actuating rod I8 passes. One edge of the rod I8 is provided with a notch J3 which, when the door Il is opened, allows the locking bar 26 to move so that the edge of the bar 26 in the opening 32 slides back of the shoulder Il on the push rod I8 thus preventing the closing of the circuit. It is possible, however, if the operator so desires, to release the locking bar 26 by pressing on the exposed tip 3i so as to retract the locking bar from engagement with the actuating rod Il.

It will be noted that when the fuse door is opened and the locking slide 26 is engaged with the actuating rod I8 to normally prevent the closing of the switch, the inclined end 3 I of the slide projects into the iuse door opening directly underneath the cover or face plate where it is distinctly visible and readily accessible when there is any occasion for the operator to release the switch to permit its circuit closing movement.

From the foregoing it will be seen that the switch provides for the usual method of operation of front operated switches and not only prevents access to the current carrying parts inside the box when the circuit is closed, but also prevents the closing of the circuit unintentionally when the door is opened and there is danger of short circuit.

I claim:

l. An enclosed switch including a box having a face plate and an opening with a hinged door, circuit making and breaking means in the box concealed by the face plate, actuating means carried by the face plate and connected to the circuit making and breaking means in the box,

' latching means carried by the i'ace plate and coacting with the door and with the actuating means to prevent operation of the actuating means when the door is open, means carried by the door to retract said latching means upon the closing of the door and a projection forming part of the actuating means and adapted to be moved in iront of the door and into the path of movement of the door for preventing the opening of the door when the circuit is closed.

2. An enclosed switch including a box having a face plate and an opening with a hinged door, circuit making and breaking means in the box concealed by the face plate, protective means in the box and normally concealed by said door but accessible when the door is open, a handle pivotally carried by the front of the face plate and connected to the circuit making and breaking means in the box, a slide carried by the face plate and adapted to interlock with the handle connection when the door is open to prevent operation of the handle. a lug carried by the door and adapted to move said slide out of interlocking position upon the closing of the door, said slide having a portion projecting into a readily accessible position adjacent the opening for the door and means independent of the slide and operably connected to the handle and projecting in front o1' the door for preventing the opening of the door when the circuit is closed.

3. An enclosed type switch including a face plate having an opening for access to the fuses, a cover for said opening, a handle hinged to the face plate, a switch actuating rod extending through the face plate and having a notch intermediate its ends, means of connection between said rod and said handle, a slide mounted on the inside of the face plate and having an interlocking connection with the notched portion o! said rod and a spring for biasing said slide to interlock with said rod and prevent closing of the circuit when the cover to the fuse compartment is open, said slide having a finger piece readily accessible for manual operation by an authorized person when the cover is open.

4. An enclosed type switch including a tace plate having an opening for access to the fuses, a handle hinged to the face plate, a switch actuating rod extending through the face plate and having a notched edge, quick make and break means oi connection between said rod and said handle, a slide mounted on the inside of the face plate and having an interlocking connection with the notched edge of said rod and a spring for biasing said slide to interlock with said rod and prevent closing of the circuit, said slide having a finger piece readily accessible through said opening for manual operation by an authorized person and means actuated by said handle for retracting said slide when the circuit is closed.

5. An enclosed type switch including a tace plate having an opening for access to the fuses. a cover for said opening, a handle hinged to the i'ace plate, a switch actuating rod reciprocable through the face plate, quick make and break means of connection between said rod and said handle, a slide mounted on the inside of the face plate and having an interlocking connection with said rod to prevent closing of the circuit when the cover is open, said slide having a finger piece readily accessible for manual operation by an authorized person when the cover is open. said cover having a projection coacting with the slide to retract the slide when said handle having a projection for preventing opening the cover when the circuit is closed.

6. In an enclosed type switch, a face plate having an opening for access to the fuses, a cover for said opening, a handle hinged to the front oi' the i'ace plate and removable thebewith, a switch actuating rod reciprocable through the iace plate. means of connection between said rod and said handle, a slide carried by the inside oi' the i'ace plate and having an interlocking connection with said rod and a spring for biasing said slide to interlock with said rod and prevent closing of the circuit when the cover is open, said slide having a finger piece readily accessible for manual operation by an authorized person when the cover is open, said cover having a projection to retract said slide when the cover is closed.

JOSEPH P. HEIM.

the cover is closed and 

